One Piece Metal Shield for an Electrical Connector

The present invention concerns a one piece metal stamping forming a metal shield to substantially completely enclose an electrical connector to provide RF-EMI shielding as well as a ground path for cable shielding.

The recent growth of the electronics industry has caused a number of problems associated directly with the growth. The large number of electronic devices currently available are often in closely spaced relationship which sometimes can cause problems when the radio frequency and electro-magnetic interference generated by one such device is absorbed by a neighboring device. This can cause erroneous generation of information with the second device and/or other undesirable results. The increasing number of electronic devices generating RF and EMI have caused the enactment of a number of requirements and regulations aimed at restricting the amount of interference that is generated by a many of these devices. This is generally handled by requiring the devices to be encased in some kind of a shielding.

There are many well known metal shields that are used in association with electronic devices and electrical connectors. An example may be found in U.S. Pat. No. 3,101,299 which shows a typical connector of the type known as a sub-miniature D. It will be seen that the insulating block carrying the terminals is enclosed in a metal housing. While this particular one is not shown terminating a shielded cable, this would clearly require only a minor modification to attach the cable shield to the metal housing. The main thing to be noticed in this patent is that the metal shell is a two piece shell which must be secured together by deforming the eyelets at each end thereof. Another example may be found in U.S. Pat. Nos. 3,879,099 and 4,062,616 in which flange portions of the two piece connector shell are crimped together. Another example of a metal shell can be found in U.S. Pat. No. 4,192,571. While this latter device is primarily intended as a strain relief, it quite clearly does enclose the end of the cable and the connector could be used for shielding purposes. However, it is again an example of a two piece metal shell which would require joining together. Any multi-part shield would have the potential disadvantage of actually creating a slot antenna should the parts not be completely joined and a gap formed.

An example of the opposite approach to multi-parts is a cast metal part such as shown in U.S. Pat. No. 3,329,925. While this does away with the possibility of creating slot antennae, it is somewhat cumbersome and is expensive to produce. It is also not cost effective from a space saving standpoint.

With the foregoing disadvantages of the prior art in mind, it is therefore the goal of the present invention to overcome these shortcomings by providing a one piece metal stamping having a face plate portion and a pair of connector enclosure shell portions each connected to an opposite side of the face portion by a respective bight. The face portion has an aperture allowing access to the mating face of the connector and can either be planar or have a metal shroud around the periphery of the aperture. The shell portions together define a connector receiving cavity and the shell portions each have depending sidewalls which interfit, in the closed condition, to completely enclose the connector. The shielding of a shielded cable would be electrically and mechanically joined to the subject shell by an externally applied crimp ring. The subject invention is particularly suitable for electrical connectors which are to be subsequently overmolded with a coating of insulative material.

An embodiment of the present invention will now be described by way of example with reference to the accompanying drawings in which:

FIG. 1 is a perspective view of the subject shell in an open condition and with a terminated connector exploded therefrom;

FIG. 2 is a perspective view of the shell of FIG. 1 after it has been closed around the connector;

FIG. 3 is a perspective view, similar to FIG. 2, showing the terminated and enclosed connector after overmolding;

FIG. 4 is a transverse section taken along line 4--4 of FIG. 3;

FIG. 5 is a perspective view of an alternate embodiment of the present invention in an open condition; and

FIG. 6 is a perspective view of the alternate embodiment of FIG. 5 in a closed condition.

The subject one piece metal shell 10 is used in conjunction with an electrical connector 12 of known configuration, such as those shown in U.S. Pat. Nos. 3,879,099; 4,062,616; and 4,200,350, terminating the end of a cable 14. The subject shell would, of course, replace the metal housings of these prior devices. The cable is of the type having a plurality of conductors 16 enclosed in an insulating sleeve 18 which in turn is enclosed in a shielding layer 20 and an outer insulating jacket 22. A crimp ring 24 is provided on the cable prior to effecting the termination with the connector.

The subject shell is a unitary member stamped and formed from a continuous piece of stock metal material and has a central face portion 26 with a pair of side shell portions 28, 30 joined to opposite sides of the face portion by bights 32, 34. The face portion 26 includes a central aperture 36 which exposes the mating face of the connector 12. This face portion 26 can also include a peripherial shroud 38 around the aperture 36, as best seen in FIG. 4. The face portion 26 is of sufficient length to provide mounting flanges and apertures at the opposite ends thereof. The side shell portions 28, 30 each include interfitting wall flanges 40, 42, 44, 46, and semi-cylindrical neck portions 48, 50.

The present invention is applied to the terminated connector 12 by first inserting the connector 12 mating face into the aperture 36 and then simply folding the side shell portions 28, 30 together, as shown in FIG. 2, bringing the wall flanges into an interfitting condition. This is best effected by forming a slight crimp along the bights 32, 34, as best seen in FIG. 4, which will serve to hold the side shell portions in the closed configuration. The shielding layer 20 of the cable would then be extended down over the neck portions 48, 50 and the crimp ring 24 slipped in place and crimped. This will serve to keep the shell members together while making the necessary mechanical and electrical contact between the cable shield and the shell.

The subject invention is best utilized with an overmolding application. FIG. 3 shows the connector and shell of FIG. 2 after an overmolding operaton with the entire outer rear portion of the shell enclosed in a molded insulative layer 52. It will also be appreciated from FIG. 4 that the crimp formed at the bights 32, 34 will aid in this overmolding operation by forming somewhat of a dam against unwanted flow of the insulating material onto the mating face of the connector.

An alternative embodiment of the subject invention is shown in FIGS. 5 and 6 and differs from the previously described embodiment primarily in the attachment of the shell portions to the face portion. In this embodiment the face portion 54 is essentially the same as the face portion 26. However, the side shell portions have been replaced by end shell portions 56, 58 which are functionally the same as the side shell portions 28, 30 but are dimensionally different. Each end shell is connected to the face portion by respective bights 60, 62. The face portion 60 also includes rearwardly directed side flanges 64, 66 while the end shells each include side flanges 68, 70, 72, 74 and mating neck portions 76, 78.

The assembly of this embodiment on a terminated connector would be the same as previously described. The end shells 56, 58 would simply be closed over the connector and crimped into place as shown in FIG. 6, with portions of the flanges thereof overlapping.

It should be noted that when the side shell portions or the end shell portions are brought into conjunction there is an overlap of the respective edge portions thereof to assure that no slot antenna, as previously described, will be created.